Ubiquitous denotes an environment in which a user can access an information communication network and use an information communication service at any time irrespective of time and place, and is attracting much attention as a next-generation paradigm of Information Technology (IT). Also, position-based technology that automatically recognizes the position of an object and provides a service suitable for the position and contexts by using the ubiquitous environment anywhere at any time becomes increasingly more important.
To provide the position-based service, the positions of user terminals are generally detected using Global Positioning System (GPS) information. However, since GPS radio wave cannot be received inside buildings, various researches are being conducted on alternative technology. Even to efficiently provide a robot service to users in an indoor space, it is important to overcome the limitation.
In the related art, proposed have been a method that recognizes a position of an object by using artificial marks disposed at an indoor ceiling, and an environment recognition method that recognizes marks using an image device to estimate a position of an object. However, the position recognition method based on the artificial mark needs to densely attach a plurality of artificial marks to a ceiling and requires a component in the robot that continuously interacts with the artificial marks on the ceiling, and thus, it is difficult to apply the position recognition method to a general-purpose mobile device.
In the environment recognition method that recognizes a mark to estimate a position based on an image device, there is a technical limitation in processing an image, and moreover, it is difficult to recognize a space having a plurality of similar sections as in public buildings.
Moreover, there is a method that estimates a position by using a Received Signal Strength Indicator (RSSI) which is an index value of a radio wave signal strength, based on a sensor network. However, even in such a method, it is sometimes difficult to steadily secure an RSSI value, and a drawback is caused when communication with a fixing device is affected by the direction or motion of a user or there is a factor that affects radio wave to largely vary an RSSI value.
Accordingly, it is required to develop a method for reducing or overcoming the limitations so as to efficiently recognize a space where a user is located in an indoor environment, but any method for overcoming the limitations has not been proposed to date.